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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Posted on 20 June 2010 by Megan Evans

Guest post by Megan Evans

When faced with the prospect of attending a climate skeptic speakers event such as the current Watts Up with the Climate? tour of Australia, anyone who understands climate change science could easily think of a plethora of reasons not to go: I don’t want to provide any further opportunity for the skeptics to propagate their disinformation, I can’t bear to hand over my hard earned money to fund their campaign, I fear I may gnaw my own arm off in frustration whilst listening to the talks, and so on. I considered all of these before attending last week’s event in Brisbane, where Anthony Watts, David Archibald and Bob Carter spoke about why we shouldn’t be concerned about climate change. Although I certainly listened to the talks, was more broke after I left than when I arrived, and found the whole occasion undeniably frustrating, it turns out that the event wasn’t really what I expected – in fact, I almost enjoyed myself.

The attendance was certainly less than Watts would have hoped for – it seems that the awareness through word of mouth wasn’t enough to pull a sizeable crowd (Noosa’s event on Friday evening was attended by just 36 people). Watts’ presentation focussed on his view that the temperature record is unreliable, suggesting that factors such as the positioning and the type of paint used on weather stations seriously undermine the accuracy of surface temperature measurements. So focussed in fact, that his 45 minute presentation consisted almost entirely on photograph after photograph of temperature stations in apparently compromising positions, with no data analysis in sight (note to Anthony: occasionally plotting the data doesn’t cut it).

Watts made a point of saying “this is how we measure climate” after every second or third photograph of a temperature station, as if as if repeating it over and over would compel people to believe it. Of course, Watts carefully ignores the fact that we also use satellites to measure temperatures all over the world. During questions I put this to him, and asked to explain why satellite and surface station measurements of temperature agree – if according to him temperatures measured on ground are all wrong. His response, that the measurements “agree somewhat”, ignores the science which confirms the accuracy of the temperature record regardless of how close to an air conditioner or hot bitumen road a weather station may be. Watts also found time to go into how the hockey stick was broken, and that the CO2 effect is saturated, and finished with a bizarre analogy with “if you put too much salt in your soup, you reach a threshold where you don’t notice any more salty taste”. That might be the case, but you’d probably end with high blood pressure pretty quickly!

David Archibald’s overdramatic and jargon-filled presentation included a stunning array of skeptic arguments, where most of the top ten got a mention. He flicked through endless graphics about solar flares and sunspots at such a pace that I could barely keep up with what they were meant to show, leaving me utterly confused about what on earth he was talking about. It seemed that Watts felt the same way, as he spent the majority of Archibald’s presentation reading over the Skeptical Science leaflet, Climate change: the full picture. Apart from explaining the importance of considering all of the available evidence before coming to a conclusion, the leaflet also discussed the minimal influence of the urban heat island effect on warming trends, so perhaps it will help Anthony with his research.

Archibald also made a point of mentioning throughout his talk that whatever he was talking about was really simple or “basic science”, before hurtling into the next argument. I was reminded of sitting through my undergraduate linear algebra classes where if the lecturer suggested that something should be easy to understand, and you didn’t understand, you felt really stupid for asking them to clarify. The pace and confusing content of his presentation effectively meant that the audience had to rely on trusting that whatever he was saying was correct. This seems unfair - someone who is unsure of how or where to find reputable information could easily be forgiven for taking whatever Archibald or the others were saying as fact.

After all, these self-proclaimed “independent scientists” are apparently free from the “corruption” that is supposedly rife throughout all of the universities, research institutions and governments throughout the world, so are effectively claiming to be the only remaining source of information about climate change that people should trust. Ridiculous as this is, the no consensus argument was a major theme that was emphasised throughout the night.

In his concluding address, Bob Carter reemphasised the take home messages of the night: 1) Temp record is unreliable, 2) CO2 effect is saturated, 3) CO2 is plant food, and 4) It’s the sun. He argued that we spend in the order of $60 billion per year on climate science, yet we are none the wiser about the state of the climate – and suggested that we could instead cure poverty with that amount of money. I was glad that Bob was concerned about the plight of people living in extreme poverty, but confused that he did not consider the impacts that climate change is already having on people all around the world.

Archibald went further to say that the best that could be done for poverty is to in fact pump more CO2 into the atmosphere, as this would provide “more food to feed the third world”. The truth is unfortunately not that simple – plants don’t just need food, they need water too – something that will be in much shorter supply with the increased frequencies and lengths of drought that climate change will bring. Carter may like to think of himself and the other speakers as “rationalists”, but the tactics that climate skeptics routinely employ to discredit science goes against the very definition of rationality.

Despite all of the misinformation, obfuscation, and frustration from hearing the same tired arguments churned out and chopped and changed throughout the night, I’m glad that I went. I’m grateful that I was given the chance to ask questions of the speakers and raise my concerns, and I was glad to be able to meet with other attendees and discuss points of disagreement in a low-key, friendly environment. One man told me that it was good just to be able to talk things through, while another thanked me for my questions. The experience made me reconsider initial resistance to go anywhere near a climate skeptics event, as it seems that although the Watts visit to Australia has yet to draw much attention from the general public at all, he and his fellow skeptics are not likely to fade away if simply we pretend they’re not there. Seeing and hearing firsthand how Watts, Carter and Archibald shamelessly mislead people made me realise how important it to try to engage in a dialogue with climate skeptics – and not just over blogs, but in person (and preferably over a drink). If that means politely sitting through a seemingly endless collection travel photos on the off chance that you could make your voice heard, then I think I can live with that. The alternative is sit back and allow the circus to roll on by.

Comments

I think this post is spot on. The only way to deal with skeptics is address them straight on. Engagement is key and sitting back to the protection of our own blogs is not the way that paradigms change. If only the boys at real climate would realize this. I think people like gavin and ray pierre should be stepping in and addressing issues at WUWT and Climate Audit as well as in person.

Wonderful post Megan and I think a great description of the event. Something that really struck me in Bob Carters summation was his argument that "we don't know" what is going on with temperature or glaciers. He said (to paraphrase) some are shrinking, some are growing, we don't measure enough to know what the mean trend is. Archibald made the old argument that there has been no warming over the past 10 years, then showed a graph that seemed to disprove his point, even though it only went through mid-2009. But wait, Archibald also argued that there is warming but it is caused by the sun. And in a recent paper, Bob argued there is warming, but it is caused by El Nino. Yet at the event he said there is no warming then a few minutes later said we don't know if there is any warming. Which contradicted Archibald's strong argument that the earth has been cooling for thousands of years and continues to so. Confused? Me too. But the contradictory nature of their arguments is a common trait of the skeptic case against AGW. All fodder for future posts. - JB

"1) Temp record is unreliable, 2) CO2 effect is saturated, 3) CO2 is plant food, and 4) It’s the sun."

So the argument is:
1) There's no warming.
2) There's can't be any warming.
3) The warming that isn't and can't happen is a good thing.
4) The warming that isn't happening is happening because of the sun.

Your argument here is invalid and thoroughly discredited. We're not interested in the absolute measurement, but the trend over time. In fact the literature will tell you that you can't make absolute comparisons between different data sources, and have to rely on relative data.

So given that, as trends assessable from the satellite and instrumental records are statistically indistinguishable from each other, your position has no merit.

You're repeating a false assertion. The satellite data shows exactly the same trend over time as the GISS, HADCrut etc. Statistically the trends are indistinguishable. Visually, the graph presented by NewYorkJ in #7 totally debunks your argument in any case. Here is is again:

The absolute difference in measured temperature is of no importance, it's the change over time that's the feature of interest. More fodder for the "how climate sceptics mislead" thread here methinks.

Poptech, you are aware that the anomalies measured by ground-based measurements are based off a 1961-1990 average, wheras the anomalies measured by satellite are based off of a 1979-2000 average? Given that average temperatures were warmer for 1979-2000 than for 1961-1990, then its perfectly reasonable that the size of the temp. anomaly measured by satellites would be smaller. That said, both ground based & satellite temperature measurements are showing a warming trend of +0.14 to +0.17 degrees per decade from 1979-2010 (with only UAH being below +0.16 due to failure to account for diurnal drift). That puts ground & satellite measurements in very close alignment, & utterly debunks Watts' weak arguments. Now, if you're not going to contribute anything *sensible* to this thread, then I might suggest its better to contribute nothing at all!

Poptech, I'm not the handiest person with plotting but even I know what "trend" means. There is no way you can say that the satellite data to which you linked "trends cooler." It is in fact trending upwards, just as the surface-based measurements are. Even a simple line plotted between end-points shows an extraordinarily similar slope (trend) among the two data sets. What is different is the offset from the x axis, but that's not a trend.

I think what Poptech is saying (correct me if I'm wrong) is both the satellite and surface data show a warming trend but that the satellite trend is not as strong.

This is in large part due to the different ways the data is processed. The RSS satellite trend is warmer than the UAH satellite trend because RSS's adjustments for satellite bias add warming in the tropics while UAH's adjustments add cooling in the tropics. The HadCRUT surface temperature trend is not as strong as the GISS trend because it doesn't include the Arctic regions where warming is strongest. Nevertheless, all these records are broadly consistent and show a statistically significant warming trend over the last few decades.

Eschenbach (of WUWT) has just produced another article trying to bury signal in noise, this time having to do with temperature anomalies on the West Antarctic Peninsula. Although there is clearly an upward trend in temperatures as reflected by all datasets, Eschenbach is -extremely- concerned about variances between each set of temperature measurements. As is usual, we are supposed to conclude that nothing can be concluded:

"All of which makes it very difficult to come to any conclusions at all … except one.

My only real conclusion is that it would be nice if we could get some agreement about one of the most basic data operations in the climate science field, the calculation of area averages of temperatures from the station data, before we start disputing about the larger issues."

The review article in Science (Science 328, 1520 (2010);
Oscar Schofield, et al) attracting Eschenbach's scorn is concerned with impacts of warming on the ecosystem of the West Antarctic Peninsula. Here are the physical symptoms of warming, as summarized in the article:

Changes in the WAP are profound (Fig. 1). Midwinter surface atmospheric temperatures have increased by 6°C (more than five times the global average) in the past 50 years (14, 15). Eighty seven percent of the WAP glaciers are in retreat (16), the ice season has shortened by nearly 90 days, and perennial sea ice is no longer a feature of this environment (17, 18). These changes are accelerating (19, 20).

On careful reading, it turns out Eschenbach's quibble with this scenario is not that there is no trend in temperature, rather that he sees it as exaggerated. Doing his own numeric massaging, he finds not a 6 degree C increase but rather "only" 3 to 4 degrees C depending on how he treats his analysis. Note that Eschenbach's own conclusion is that WAP temperatures have risen far faster than the increase in global average. Eschenbach is in significant agreement with the summation of the paper he's criticizing, but you'd be hard pressed to notice the inconvenience by reading his own words because that conclusion is left buried between the lines.

This is pretty much classic "How climate skeptics mislead" material. Zero in on whatever defects are available regardless of whether they have explanatory power, ignore the big picture, make sure readers end up lost in a myriad of details that are interesting but not really significant.

Broadly your post is correct. However, any difference in trend between the different data sets is not statistically significantly different.

The easiest way to estimate this effect is to observe thatthe 95% confidence interval of the correlation coefficient of anomaly against time overlap for all three main data sets. However, as this approach does not correct for autocorrelation (time series property) it's insufficiently conservative.

I think attending sceptic meetings and asking questions is important. However, public debates like Tim Lambert vs. Monckton is not a good idea as it implies a false equivalence between scientists and deniers.

I'm glad to see that you are engaging with the sceptical arguments. As someone who has tried to follow this issue I still find myself at a loss to decide which way to jump. What seems to be lacking is a serious high level public debate on the arguments for and against man-made climate change so that non-experts such as myself can make informed judgements.

That said however I would still insist that a consensus in science is something that forms around an issue that is by its nature controversial. No consensus is required with respect to Newtonian science since it is about as uncontrovesial as anything in science can be. So even if we accept the theory of man-made global warming it is very much in the nature of a judgement and not a certainty. Science does not deal with certainties but with knowledge of overwhelming probabilities.

The place of science in life also needs to be taken into cosideration. How we act in relation to advances in scientific knowledge is not a push-button affair. There is a somewhat Mathusian tone to the pronouncements of many proponents of man-made global warming that perhaps explains some of the resistance to their scientific case.

'The science says so' is not an acceptable argument for the complete re-allocation of society's resources. Firstly because even scientific othodoxy is not beyond question but also because we must take into consideration many other things such as ethical, economic, political, considerations alongside the scientific knowledge.

Having said all that I do recommend your site to any sceptics that I come across and it has made me a bit more sceptical about the sceptical science. I still need that public debate though!

The continuation of the "CO2 is plant food" line, first invented, if I remember correctly, by one of the oil companies, sums up the approach of people like Carter. He must know, surely, at some level of consciousness that this is meaningless. Has he never spoken to a botanist in his university about this? Has he read nothing about it? Every sentient being in the universe must be aware that CO2 is not limiting on plant growth in the real world, where limits are set by water, sunshine, temperature, soil nutrients, soil trace elements, competitors, pests and diseases, and so on. Except in the laboratory conditions of a greenhouse, where all these other factors are supplied in abundance, increasing CO2 can have little if any effect. Even in the greenhouse the effects are minimal and may have unforeseen consequences like increasing toxins.

One point of "CO2 is plant food" is presumably to make people think that this is going to lead to a brave new world of giant pumpkins and waving fields of grain, but that is clearly not going to happen, even if other factors are kept constant. And Carter, being Australian, must know that the other factor are not constant as we see increasing crop failures due to record high temperatures and record low rains.

And the other point, I guess, is that they are trying to subliminally suggest that it doesn't matter how much CO2 we pump out, it will all get taken up by increased plant growth. But we know, and they know, that this isn't happening because CO2 levels keep rising. Furthermore we know, and they know, that it didn't happen in the past because, wait for it, climate changed in the past.

Finally, what on earth would make you think that plants adapted to the CO2 levels of up to a couple of hundred years ago, would have the potential to react to the burning of millions of years worth of previously locked up carbon in a matter of 200 years?

So Mr Carter keeps saying "Co2 is a plant food" why? because he believes it adds substance to what he must know is an increasingly weak argument, and because he thinks it makes CO2 sound cuddly and friendly.

Every one of the points that Megan records could be analysed in the same way. So why do they keep trotting them out in the absence of new data? It all feels a bit like a gospel meeting where the preacher repeats the same old biblical lines, knowing that his audience will feel comforted by the familiarity, and certainly won't ask questions. An impression, of substance and meaning, will have been created out of material which in real life has neither.

"What seems to be lacking is a serious high level public debate on the arguments for and against man-made climate change so that non-experts such as myself can make informed judgements. "

Unfortunately, scientific differences cannot be decided by public debate and a vote. Nature is not a democracy!

Politicians have little choice but to follow the scientific consensus, and I hope that you can see what that is. Unfortunately, there are powerful vested interests (political and economic) who do not want the full implications of the scientific consensus to be carried through. The public have a right to reject the implications of the scientific consensus, but that leads us to a place where people are preferrring short-term comfort over long-term safety.

A comprehensive picture of how doubt in the scientific consensus is a manufactured phenomenon can be found in Oreskes and Conway's book

Some thoughts around the following argument: "The truth is unfortunately not that simple – plants don’t just need food, they need water too – something that will be in much shorter supply with the increased frequencies and lengths of drought that climate change will bring."

If the temperatures of the oceans are rising, more water vapour will be transferred to the atmosphere (per day, or whatever). That is physics. The same goes for lakes, if land temperatures rise. Evaporated water has to come down again, hence more rain than today. Wet and warm ground evaporates even more water back to the air, and so on.

Were is the proof that a warmer ocean will produce less rain, and more drought?

00

Response: What has been observed over the last century is an intensification of the hydrological cycle. Wet areas are getting wetter and drier areas are getting drier. This is because with warmer temperatures, you get evaporation which leads to heavier rainfall but also drying out of drier soils. Doing a post about this has been on my to-do list for a while but I'll move it up the priority list, seeing how popular the 'CO2 is plant food' argument is becoming.

Argus - I know this isn't directly answering your question, but I think its important to consider that even if warmer oceans produced more rain, the sea level rise from increased temperatures will inundate arable land and also displace large numbers of people. If the concern is about producing food to feed people, then extra rain isn't going to help if your crops are under seawater (and if you don't have anywhere to live).

Argus #25: "Were is the proof that a warmer ocean will produce less rain, and more drought?"

That's not happening, and that's not the issue here. More heat produces more evaporation, and more precipitation. The question is where and when? If the distribution does not stay constant, we can have all sorts of effects happening, and IF the variance increases, we can expect more extreme weather, harder rainfalls etc. Unless the total amount increases a lot, we can get more droughts ALONG WITH more precipitation , it could be considered as simply a statistical effect.

So, the issue is, does the variance stay constant, or even decrease? That MAY happen, but with a lot more energy transfer, the outcomes could tend to be predominantly in the other direction. Observation is, it HAS become warmer. Question is: Have we got as much, less, or more extreme weather along with that?

Argus #27:
"Yes, I am aware of the effects of rising sea levels. My question was an entirely different one. From where did you get the information that water "will be in much shorter supply" in a warmer climate? "
May I suggest that you try and look for answers to that yourself before you ask here? And, then, refute the papers which deal with this?

I have seen some remarks on the fact that the satellite data tends to exaggerate the highs and lows of the ENSO signals. I think you can see that in Barry's graph in #20. The remark never had an explanation as to why.

00

Response: My understanding was the lower troposphere shows more exagerated highs and lows compared to the surface temperature record due to the same reason we expect a tropospheric hot spot - surface warming affects the moist adiabatic lapse rate in such a way that it leads to an amplification of any surface trends. But there may be more to it than that - other commenters, feel free to enlighten us.

@Argus: evaporation and absolute humidity will rise wherever there is water to evaporate. In very dry areas, this will probably not be the case. Further, according to the Clausius-Clapeyron equation, the saturation vapor pressure also rises with temperature (at a rate of ~7% per degree Celsius). As a consequence, relative humidity will remain more or less constant. However, there will be more water vapor in the atmosphere available for heavy showers. After rainfalls, it may take a longer time to achieve the saturation vapor pressure again (until there is sufficient water vapor to form clouds and rain drops). One can expect that there will also be prolonged periods without rain fall, even in relatively humid areas, while the soil may not be able to take up all the water from heavy showers. Things are tricky...

Poptech is correct that the UAH trend is slightly lower than all the other trends (including the other satellite data set, RSS, which is essentially identical to the surface temperature trends).

We had this exact same discussion last month, right down to people misunderstanding Poptech's claim and thinking he was saying that UAH trended negative (see Poptech's comment here, and the ensuing discussion).

As I pointed out at the time, it's actually amazing how close the agreement is among the different data sets. Here are the trends, 1979-present for the various temperature data sets (in degrees C/century):

I think "CO2 is plant food" was invented 1/2 a billion years ago. Surely every sentient being knows that CO2 is a food source for plants. I think what you are alluding to is that traditionally people haven't considered CO2 in the way they consider your long list of factors because it isn't seen as variable over the different ecosystems of the planet. That's not to say that increasing (or decreasing) CO2 won't have an impact on growth. We should consider what affects the changes in CO2 levels over the past century have on plant growth. I've seen the videos of planets growing faster in higher CO2 environments in the lab but obviously here other factors have been maximized to allow this to occur.

Research on satellite data show a greening planet over the past few decades. The authors of this work speculated a link to temperature but it's worth noting that ranges hadn't greatly increased rather vegation had become more dense. It possible to link this with increased CO2 as well. I don't particularly favour either.

It strikes me it's worth also considering the impact specifically on crop plants. Agriculture already attempts to maximise growth by controlling the factors you list in your post. Given that this is more akin to the experiments attempted in the lab it's worth considering that specifically agricultural plants might benefit from the extra CO2.

"Yes, I am aware of the effects of rising sea levels. My question was an entirely different one. From where did you get the information that water "will be in much shorter supply" in a warmer climate?"

Along with what others have said, some of the most productive ag land in the US - the interior valleys of California - are dependent on snowpack for irrigation water in spring and summer. Warming has an obvious implication for snowpack...

Another excellent post, followed by a predictably interesting and informative discussion. Although I'd like to return to Megan Evans original post:

"When faced with the prospect of attending a climate skeptic speakers event such as the current Watts Up with the Climate? tour of Australia, anyone who understands climate change science could easily think of a plethora of reasons not to go... "

I believe every climate "skeptics" public presentation should (must) be attended by folks who understand the science and who are frustrated at the endlessly rehashing of false arguments and lies.

Besides, being there to question assertions made ~ it's a great place for the more proactive among us to hand out our own fliers, pointing out fallacies plus a list of valuable resource links (beginning with Skeptical Science since I believe this is the clearest, most accessible (starter) resource for laypersons who want to focus on understanding the science behind global warming).

Scientists such a PhD Abraham are starting to step up by compiling excellent understandable presentations/arguments along with documentation challenging contrarian misrepresentations.

Now, the time has come for informed, concerned laypeople to help get that word out. And every AGW "skeptics" public presentation is a new opportunity to teach the poorly informed, that should not be passed up!

"While such changes in salinity would be expected at the ocean surface (where about 80 per cent of surface water exchange occurs), sub-surface measurements indicate much broader, warming-driven changes are extending into the deep ocean," Mr Durack said.

The paper also confirms that surface warming of the world's oceans over the past 50 years has penetrated into the oceans' interior changing deep-ocean salinity patterns. The study, co-authored by CSIRO scientists Paul Durack and Dr Susan Wijffels..."

{"These broad-scale patterns of change are qualitatively consistent with simulations reported by the Intergovernmental Panel on Climate Change (IPCC)."}

David Horton at 17:37 PM, it's possible Bob Carter might just be promoting the CO2 is plant food line because he is aware of real world FACE wheat trials that have produced results that contradicts much of what you claim. A link to the trial results is in my post above.
Results from the first three years of the experiment include increases in biomass, which in agriculture, translates into increases in yield with about a 20% increase in yield because of the elevated CO2.

00

Moderator Response: Detailed discussion of CO2's benefits for plant growth should be continued on this other thread, where some comments already exist about FACE trials: CO2 is not a pollutant

Thank you Megan for an excellent article.
Having read the various discussions as I made my way down here to post this reply I couldn't quite avoid seeing some glaring anomalies with the interpretations some people have regarding things like the CO2 plant food and increased temperature = increased rainfall. Definitely worth an article of explanation.

Oh and then Marty with his posting where he said:

'The science says so' is not an acceptable argument for the complete re-allocation of society's resources. Firstly because even scientific orthodoxy is not beyond question but also because we must take into consideration many other things such as ethical, economic, political, considerations alongside the scientific knowledge', statement.

Well when I read your posting I couldn't help thinking that to not act to stop AGW is hardly 'ethical'. Seems to me that if something is going to destroy the planet then surely it would be 'ethical' to stop doing whatever it was that was causing this to happen? Or am I missing something here?
Then you cite 'Economic' considerations. Ooh! Well now when everything has dried up to a crisp and there is nothing to eat or drink then I guess you can always try eating the money because it will have stuff all use for anything else.......unless you get cold at night then you can burn it but watch out for all that carbon your releasing.

Finally we come to 'political' considerations.
Last time I checked the only reason my politician contacted me was to persuade me to vote for him at the recent general election (UK) promising to deal with all the climate issues in one fell swoop and in one term of office. Immediately after they get elected they cut back on several highly important initiatives to curb climate changing gases because they cost money and they need to save money. Talk about short sighted and blinkered. So don't mention politicians. They don't give a damn until it comes to securing their seat in office and a nice fat salary thank you very much and then they are all over you like a rash promising the Earth.

Sorry for being somewhat cynical but when we need to get things sorted to save our lives I despair at the idiots like Watt's and Monckton who deliberately try to deceive people by exploiting their ignorance of science and the lack of support for legitimate science research and interpretation from people in power (aka politicians) and the corporate giants who bumble along with the business as usual model claiming that the people they employ would lose their jobs if controls were put in place and this would harm the economy.

Well there will be far less economy let alone jobs or life on the third rock from the sun unless we DO stop AGW or at least reduce it. Sadly that won't happen because there are still too many ignorant people out there who will not listen, cannot listen or don't even come within ear shot of the listening to the truth. Its a lost cause unless the truth gets out there so citizenschallenge posting #35 your posting made excellent sense. I could not agree more. We need to get the info out there before the naysayers destroy the last chance we have.

Re: Moderator's response to my comment - Thank you, I will be an interested reader of a possible future post around rain and drought.

Re: SNRatio#28 - More of all extremes, as a result of increasing volumes and greater statistical variance, is an important aspect. I think we have to continue observing and asking questions for quite a while before we know.

Re: SNRatio#29 - I thought it was OK here to question, and discuss, claims that were made in the top post...

Re: dhogaza - Snowpack is a new word for me (my native language is not English), but I certainly see your point. In my country we have a lot of that, and a lot of hydro-electric power as well...

Odd coincidence w/regard to Argus' question and some of the replies, this popped up while I was browsing newspapers. Return of the rainy season in China:

Earlier this year, south-east China endured its worst drought in living memory, but in the past week, some places have been inundated with three times the average rain for this period.

Weather or climate? Who knows, but it's in keeping w/predictions. Warmer air becomes turgid with moisture, refuses to give it up and then -bam- out it comes when the temperature is finally forced to drop by adiabatic cooling or whatever cause.

Oops. Reading further in the article:

Southern China experiences flooding almost every summer, but the pattern may be changing. According to the Beijing climate centre, extreme weather events have increased in recent years. It says droughts are becoming longer and rainfall comes in more intense and damaging bursts.

s1ck #31 - Thanks for an interesting comment about saturation vapor pressure and relative humidity! And also about dry areas vs humid areas. But why do we have these persistent dry areas? Why is Sahara a desert now (but not 9000 years ago)? And why is there mostly rain forests at similar latitudes around the world (except for the nearby Arabian Peninsula)?
Is there anything we can do about it?

Maybe there is! I remember reading an article in Nature in the 70's about a proposition to open up a tunnel to flood the Qattara Depression with water from the Mediterranean. It would provide hydropower for decades or longer, and eventually create a large lake (the size comparable to Lake Erie) in the desert. A lot of water would of course evaporate in the heat, creating clouds and rain within a much greater area. I think it sounds like a grand project, which 30-40 years ago did not seem so interesting, maybe, since Libya had so much oil anyway. But now? Reduce oil use, get electric power, improve the local climate, freshen up the Mediterranean. Why not try this? A climate experiment in real life..

Yes, Ian, but that's not exactly a part of the paper that Johnd would want to cite, because quite obviously it does not support his "CO2 is plant food" and higher CO2 concentration will be beneficial talking points, now does it?

Quite the opposite, in fact, as it confirms what the climate science community has been saying all along: CO2 fertilization will be for naught in the face of increased heat stress and unpredictable precipitation and/or ground water supply.

Argus, as to why there are generally rainforests in the tropics and deserts around 30 N/S ... that's an effect of the Hadley Cells (moist air rising in the equatorial region expands and cools, causing precipitation, while the sinking air at the other end of the Hadley cell is dried out). Warmer climate conditions generally see a wider ITCZ and a poleward expansion of the whole system, so, for example, during the Holocene Optimum much of the Sahara was a little bit wetter, because of this poleward shift.

Argus, I too remember discussion of using the a pipeline or canal to the Qattara Depression to generate hydropower and create an inland sea. There's some interesting history of it in Wikipedia:

http://en.wikipedia.org/wiki/Qattara_Depression

One obvious issue would be the buildup of salt over time, left behind by the evaporating seawater.

'Unfortunately, scientific differences cannot be decided by public debate and a vote. Nature is not a democracy!' Quite true. Nature is not a democracy. But I take it that you would not be in favour of a Green Dictator who would enforce green policies irrespective of people's needs and desires. Or maybe you would!

Mythago says 'to not act to stop AGW is hardly 'ethical'' Ok. So given that having a child is just about the worst thing that anyone could do for their carbon footprint would you be in favour of some kind of eugenics program or something like China's one child policy? such measures would be highly effective and perfectly in line with the science, but would they be ethical?

As far as political considerations go maybe you might be in favour of some kind of un-elected scientocracy running the world but I certainly wouldn't.

Unfortunately this is just the kind of high-handed response to legitimate concerns about how the science integrates in with the world of human affairs that makes people go running to the sceptics or just throw their hands up in despair about the whole issue.

Even if the science were all black and white - which it isn't - then the relationship between the science and what we, as a society, do about it is not at all black and white.

Marty, flamboyant speculations about eugenics and the like are fun rhetoric to write and read but they're not very useful.

As we've learned over the past few hundred years, the combination of better education, better health care and better equality between sexes appears to naturally produce a decline in birth rates to more sensible levels. So there's no need for draconian laws such as China substituted for these improvements. We know this already. Your point about the impact of population is well taken, though.

Meanwhile, as to the transference of scientific knowledge into the public policy arena, we've already seen numerous successful examples of this. Strong encouragement of vaccination so as to promote "herd immunity" from disease, public sewer and water systems, cases such as these were the upshot of scientific investigation leading to reasonably sound predictions not confirmed until public policy was adjusted to follow scientifically derived recommendations. In some cases (public water and sewer systems) temporary controversy arose as these improvements were implemented because they presented a threat to established commercial interests. Note that vaccination was a new market not posing a threat to existing commercial concerns and thus was embraced with relatively little controversy compared to public health initiatives such as sewer systems.

This business of C02 is not really new as a general phenomenon. It happens to be particularly difficult to address as well as controversial because indeed we do have a serious dependency on fossil fuels and as well the commercial incentives for established players to maintain inertia are also very large.

"'Unfortunately, scientific differences cannot be decided by public debate and a vote. Nature is not a democracy!' Quite true. Nature is not a democracy. But I take it that you would not be in favour of a Green Dictator who would enforce green policies irrespective of people's needs and desires. Or maybe you would!

...

As far as political considerations go maybe you might be in favour of some kind of un-elected scientocracy running the world but I certainly wouldn't. "

How does Marty get from "scientific differences cannot be decided by public debate and a vote. Nature is not a democracy" to a conclusion that this implies a political dictatorship run by scientists!

Marty - please get real.

1, Science is what it is. CO2 is going to do its thing regardless of your political beliefs.

2. The legitimate debate centers around *policy* - what to do about the implications of what science teaches us. Feel free to debate that to your heart's content. If you want to argue that the correct response is to do nothing, well, do so.

Marty, nobody here has advocated imposing a global dictatorship or eugenics or a forced one-child policy. That's not a really helpful approach to discussion here; you would be better off developing arguments that don't involve the assumption that those who disagree with you are evil.

Science is not a democracy. It's also not a dictatorship. Ideally, it's a meritocracy. In the long run, scientific claims that don't provide useful explanations of how the world works will lose out to those that do provide better explanations, though it can take decades (or longer) for this process to work out.

That's separate from the question of how a society should respond to what science says. The question "If we double the CO2 concentration of the atmosphere, what consequences should we expect?" is a scientific question. The question "Are those consequences worth trying to avert, and at what price?" is a value judgment, and in a democracy the latter question is absolutely a subject for the democratic process.